U.S. Pat. No. 7,634,347B2 discloses a refueling system and method. The known refueling system includes: a fuel tank; a canister configured to adsorb fuel vapor generated inside the fuel tank; a canister drain cut valve coupled to the canister and configured to discharge air; an ignition sensor configured to detect whether the ignition of the combustion engine is switched on or off; and a refueling controller configured to open the canister drain cut valve when the ignition sensor detects that the ignition of the combustion engine is switched off. A method for refueling a motor vehicle can use the refueling system.
It is a disadvantage of the prior art that the maximum resolution of the level sensor and the maximum height that it can read (relative to the height at which rated capacity is met) limit the useful capacity of the vehicular liquid storage tanks. Any optimizations in that respect would require the change of hard-tooled components, which is disruptive and costly.
German patent application publication no. DE 199 01 080 A1, discloses a tank for a vehicle with a fuel container and at least one degassing device that can be closed by a valve, over which the gases in the fuel container can escape during a filling operation. To avoid expensive retooling and redesign of the degassing device of such a tank, when a different fuel container is to be used, it is proposed to open and close the degassing of the fuel container by means of a valve controlled by a controller. DE 199 01 080 A1 discloses monitoring the filling rate and filling level in order to determine the point in time at which the valve is to be closed to end the filling operation, and applying a smooth closing function to the valve so as to avoid a pressure shock. Hence, the system of DE 199 01 080 A1 is not able to terminate the filling operation at the most optimal point in time (i.e. with a maximally filled tank) when the filling operation is started with a fill level that is already above the highest level that can be correctly measured by the gauge.